Control device for automatic and semiautomatic firearms



W. C. ROEMER CONTROL-DEVICE FOR AUTOMATIC AND May 31, 1949.

SEMIAUTOMATIC FIREARMS 4 Sheets-Sheet 1 Original Filed March 30, 1945 Awavroe WILLIAM 6. R05 MER 1/ wfw ,4 7 roe/vars May 31, 1949. w. c. ROEMER 2,471,779

CONTROL-DEVICE FOR AUTOMATIC AND SEMIAUTOMATIC FIREARMS Original. Filed March 50, 1945 4 Sheets-Sheet 2 Awflvroe WILLIAM C. ROEMER A r TOk/Vf rs May 31, 1949.

W. C. ROEMER CONTROL-DEVICE FOR AUTOMATIC AND SEMIAUTOMATIC FIREARMS 4 Sheets-Sheet 5 Original Filed Marcl :50, 1945 l l A s x m rm um .i

/NVENTOR a m a T M A A I U May 31, 1949. w. c. ROEMER CONTROL-DEVICE FOR AUTOMATIC AND SEMIAUTOMATIC FIREARMS 4 Sheets-Sheet 4 Original Filed March 50, 1945 l ll! i oh R 5 N E R E 0 r K m N 7 /CM/ Patented May 31, 1949 UNITED STATES PATENT OFFICE CONTROL DEVICE FOR AUTOMATIC AND SEMIAUTOMATIC FIREARMS William C. Roemer, New Haven, Conn., assig'nor to Olin Industries, Inc., New Haven, Conn., a corporation of Delaware Original application March 30, 1945, Serial No. 585,666. Divided and this application April 6,

1946, Serial No. 660,184

2 Claims.

Thepresent invention relates to improvements in self-loading firearms and relates more particularly to improvements in control-devices for controlling the functioning of a self-loading firearm, whereby the said firearm may be selectively caused to operate either as a full automatic or a semiautomatic firearm.

The present application constitutes a division of my co-pending application Serial No. 585,666,

now Patent No. 2,469,053, issued May 3, 1949, filed longitudinal section of the firearm-structure with March 30, 1945. the parts in the same positions in which they are One of the objects of the present invention shown in Fig. 4 and with the sear-actuating bar is to provide simple, reliable and effective conp rimp sed in the fo egro d fo p po s of trol-means whereby a self-loading firearm may illustration and with the box-magazine omitted; be readily set to function either as an automatic F 6 s a top 01 plan view of the trig as a semiautomatic firearm plate unit including the rear-portion of the sear- Another object of the present invention is t actuating bar, but omitting the box-magazine; provide a supefior contmbdevice or mechanism Fig. '7 is a perspective view of the sear-actuatfor self-loading firearms whereby in addition to ng bar, detached; controlling the functioning of the firearm either 3 is broken tragnsverse Sectlonal as an automatic or semi-automatic firearm, the takn onfihe lme said control-device may also be utilized to render 9 15 perspective the hammer the firearm safe against discharge. tackled;

- A further object of the present invention isv i 10 1s Simllar, of theS.ecndary'Sea1:; to provide a superior control-device of the charis a View Side a' of h 3 acter referred :to and which is especially well compnsmg the plunger and spun? 1:01 yleldmg' suited for installation in the general type of milithe sear'actua'tmg bar m Its re'armost tary firearm known as the Carbine M1, Without requiring extensive reorganization of the 12 1S View similar to but Showing parts of such a military firearm th eontrol-stem of the control-unit turned into With the above and other objects in view as pqsltlonjoy semla'utomatic fire and showmg will appear to those skilled in the art from the mgger m and the hammer temporarily cocked by the secondary-sear; present disclosure, this invention includes all fea- Fig 13 is a View similar to Fig 12 but show tures in the said disclosure which are novel over mg the hammer as released by the secondary g 39; gg i im cl'almed m my sear and releasably held by the primary-sear 1 co pe 1 preparatory to efiecting the discharge of the firemhe aCCOmPanYmg drawmgs' m m arm by a manual rearward draft upon the fintam modes o.f carry1n g out the present invention ger piece of the trigger which latter is Shown are shown for illustrative purposes: 40 in its f rd position; L a b slde Fig. 14 is a broken perspective view partly in recelver' tngger'plaFe the rear'portlon section of the control-unit and associated feaof the barrel and associated elements of a selftures together with a portion of the triggepplam loading firearm embodying the present 1nvent1on, unit the ,controLumt being Shown in a posi and show1ng the selector-lever set for full au tion which it assumes to enable the firearm to mat1c fire and showing the trigger held in its operate emiautomatically; pulled position and the hammer and .associat- 5 is a View similar Fig 4 but Showed parts at the instant of the discharge of the ing the control-unit turned into position to enable the firearm to operate as a full automatic Fig. 2 is a broken view in vertical centralfirearm; and longitudinal section of the portion of the barrel i 1 is view similar to Fig 5 but Showand associated features lying at and immediateing the control-unit moved transversely to renly forward of the portion shown at the right of der the firearm"safe. Fig. 1; The particular self-loading firearm herein Fig. 3 is a broken top or plan view of the showchosen for purposes of illustrating one form of 3 the present invention, includes among its main features a receiver III, a barrel I I, a trigger-plate unit I2, a breech-bolt I3, an action-slide I4, and a sear-actuating bar I5.

At its forward end vthe receiver I has the rear-end of the barrel II secured to it, while the trigger-plate unit I2 is secured in any suitable manner to the under face of the receiver I0 beneath a mechanism-receiving chamber I6 formed in the said receiver and accommodatin the breech-bolt I 3 in its upper-portion.

The breech-bolt I3 is mounted in the upperportion of the mechanism-receiving chamber I6 in the receiver I I] in such manner as to be guided for both longitudinal-reciprocation and transverse-oscillation in a manner generally similar to the breech-bolt employed in the well known Garand military rifle. The said breech-bolt is provided adjacent its forward end with two oppositely-extending locking-lugs I! and I8 formed integral therewith.

The respective rear faces of the locking-lugs I1 and I8 above referred to are adapted to be engaged with and disengaged respectively from forwardly-facing locking-abutments I9 and 29 respectively formed in the opposite side walls of the receiver II]. The right locking-lug I8 is formed with a radially-extending actuating-lug which enters a cam-recess 22 formed in the inner face of the enlarged rear-portion 23 of the action-slide I4, as is especially well shown in Figs. 1, 3 and 4. The said rear-portion 23 of the action-slide I4 has an operating-handle 24 pro jecting radially outwardly from it, by means of which latter the said action-slide may be manually retired when desired.

The enlarged rear-portion 23 of the actionslide I4 is integrally connected by a bar-portion 25 to a crosshead 26 located at the forward end of the said action-slide. The said crosshead 26 extends beneath the barrel I I and is formed with an upwardly and forwardly opening clearancerecess 21 for purposes as will hereinafter appear.

At its rear the crosshead 26 is provided with an integral rear wall 28 which latter has its forward face normally engaged with the rear end of a stem 29 forming an integral feature of a piston generally designated by the reference character 39.

In addition to its stem 29,- the piston 30 above referred to also includes a relatively-large diametered head SI and reciprocates within a rearwardly-opening piston-chamber 32. Said piston-chamber 32 is located in a cylinder-lug 33 formed integral with and depending from the barrel I I at a point slightly forwardly of the front end of the receiver I6 and normally accommodated within the clearance-recess 21 in the crosshead 28 of the action-slide I4.

The rear-portion of the piston-chamber 32 in the cylinder-lug 33 is internally threaded to receive an externally-threaded tubular stop-member 34 through the interior of which latter the stem 29 of the piston 30 extends, as is especially well shown in Fig. 2. Leading forwardly and upwardly from the forward end of the pistonchamber 32 is an inclined gas-passage 35 communicating at its forward upper end with the bore 36 of the barrel I I, to thus permit gas under pressure to impinge against the forward end of the piston 30 to drive the same rearwardly in a manner as will hereinafter appear.

The trigger-plate unit I2 is formed in its rearportion with an upwardly-opening recess 31 in which is pivotally mounted a trigger 38, as is espe- '4 cially well shown in Figs. 5, 12 and 13. The said trigger 38 is provided with a depending fingerpiece 39 which extends within a loop-like triggerguard 40 forming an integral feature of the lower rear-portion of the trigger-plate unit I2.

The trigger 38 is pivotally connected to the trigger-plate unit I 2 within the recess 31 therein, by means of a transverse pivot-pin 4|. The said trigger is formed with a forwardly-extending stop-finger 42, the forward end of which is adapted to extend downwardly into an upwardlyopening recess 43, which latter serves to connect the forward lower-portion of the recess 31 and the upper-portion of a transverse passage 44. The said passage 44 extends transversely through the lower part of the trigger-plate unit I2 at a point immediately forwardly of its trigger-guard 40.

The transverse passage 44 above referred to, accommodates, with capacity for both turning and reciprocating movement, the control-stem 45 of a control-unit generally designated by the reference character 46. The said control-unit also includes a plate-like control-lever 4'! which is rigidly attached to the right end of the said control-stem 45. The said control-lever is located adjacent the right side of the lower-portion of the trigger-plate unit l2 and is adapted to effect the turning movement of the control-stem 45 through an angle of about 90 for purposes as will hereinafter appear.

About midway of its length the control-stem 45 of the control-unit 46 is cut away to provide a relatively-slender web 48 of substantially-triangular form in cross section. as is especially well shown in Figs. 5, 12 and 13. The said web has a relatively-short face 49 and a relatively-long face 50 extending at a substantial right angle to the face 49 just referred to. The relatively-short face 49 of the control-stem 45 is formed about midway of its length with a transverse detent-rib 5 I, and similarly the relatively-long face 50 is also formed with a detent-rib 52 forming in effect a continuation of the detent-rib 5I but extending at a right angle thereto.

Adapted to coast selectively with either of the two faces 49 and 50 of the control-stem 45 as well as with the respective detent ribs 5| and 52 thereof, is a detent-plunger 53. The said detentplunger is mounted for reciprocation substantially lengthwise of the firearm-structure in a substantially-horizontal socket 54 formed in the lower-portion of the trigger-plate unit I2 immediately forwardly of the trigger-guard 40 thereof, as is especially well shown in Figs. 5, 12 and 13. Engaged with and thrusting rearwardly upon the detent-plunger 53, is a helical detentspring 55 located in the forward-portion of the socket 54.

Pivotally mounted upon the pivot-pin 4I serving as a mount for the trigger 38, is a lever-like primary-sear 56 having a transverse slot 51 located about midway of its length and through which the said pivot-pin 4I extends. The slot 51 is designed and adapted to not only permit the said primary-sear 56 to pivot about the pivotpin 41 but also to permit the said primary-sear to have limited lengthwise bodily movement with respect to the said pivot-pin and the trigger 3B.

The rear end of the primary-sear 56 is adapted on occasion to engage with the forward face of a transverse stop-rib 58 formed on the upper rear-portion of the trigger 38. About midway of its length, the primary-sear 56 is formed with a depending-lug 59, against the rear face of which V trigger 38.

presses the forward end of a helical sear-spring 6!! which is carried in the upper-portion of the The said sear-spring 60 exerts a constant-but-yielding effort to turn the primary sear 56 in a counterclockwise,direction (as viewed from the right) so as to lift its forward end, and also exerts a yielding effort to bodily move the said primary-sear forwardly to the limit of the movement permitted by its transverse slot 51 and the pivot-pin M.

The trigger 38 and the parts carried thereby are yieldingly urged to turn in a counterclockwise direction by a trigger-spring BI carried in the rear-portion of the trigger-plate unit I2 and pressin downwardly upon the upper rear-portion of the trigger 38, as is shown in Figs. 5, 12 and 13.

The forward end of the primary-sear 56 is adapted to releasably engage with a rearwardlyfacing primary-cocking abutment 62 formed upon the lower-portion of a pivotal-hammer 63. The lower-portion of the said hammer extends into the upwardly-opening-recess 31 in the trigger-plate unit I2 and is pivotally mounted therein upon a transverse hammer-pin 64. The said hammer '63 is urged to swing in a clockwise direction by a helical hammer-spring 65 which acts through the intermediary of a plunger 66 extendin through the said hammer-spring 65 and thrusting at its forward end against the hammer63.

The upper forward end of the hammer 63 is adapted to strike the head 61 of a firing-plunger I33 which is mounted for reciprocation in the breech-bolt I3 and is designed to effect the discharge of the firearm in a manner well known in the art.

On its forward edge the hammer 63 is formed with a downwardly-facing secondary-cocking abutment 69 which is adapted to be engaged by an upwardly-facing secondary-cocking abutment 5 8 formed on the rear edge of a substantially-vertical secondary-sear I I.

The secondary-sear II above referred to is accommodated in the forward-portion of the recess 37 in the trigger-plate unit I2 and is mounted at its lower end for pivotal movement upon a transverse pivot-pin 12. The said secondarysear is formed in its upper end with an upwardly-and-laterally-opening coupling-notch 13 which receives a coupling-finger 14 formed integral with and projects inwardly from the rearportion of the sear-actuating bar I5 before referred to. The rear-portion of the said searactuating bar extends along one side of the forward-portion of the trigger-plate unit I2, and at its forward end projects into a position adjacent the cylinder-lug 33 on the barrel II. At its forward end, the said sear-actuating bar I5 is formed A with an upwardly-extending finger 15, the substantially-vertical rear face of which constitutes a tripping-abutment I6. The rearwardly-facing tripping-abutment It just referred to is adapted to be engaged by a forwardly-facing trippingabutment Tl formed on the action-slide I4 at the junction of its bar-portion 25 and its crosshead it, as is especially well shown in Figs. 1, 3 and 4.

About midway of its length the sear-actuating bar !5 is formed with a transverse and longitudinalslot I8 through which extends a transverse coupling-pin I9 supported in the firearm-structure. The said' slot I8 permits limited lengthwise movement of the sear-actuating bar I5 relative to the coupling-pin 19 and relative to the receiver I0, barrel I I, trigger-plate unit I2 and associated parts.

For the purpose of yieldingly holding the searactuating bar I5 at the limit of its rearward movement, the said bar is formed in its rear adjacent its coupling-finger 74, with a forwardlyopem'ng spring-pocket in which is located a helical spring BI and the rear-portion of a plunger 82. The forward end of the said plunger bears against the adjacent portion of the triggerplate unit I2, as is shown particularly well in Fig. 6.

The action-slide It is yieldingly urged forwardly by a helical breech-closing spring 83 having its rear end seated in a spring pocket 84 extending longitudinally of and opening forwardly through the right side Wall of the receiver It, as is shown in Fig. 1. The forward-portion of the said breechclosing spring 83 encircles a breech-closing plunger 85 and thrusts the same forwardly-by abutting against the rear face of an integral annular-collar 85 formed adjacent the forward end of the said plunger. The forward face of the collar 86 just referred to bears against the adjacent rear-portion of the cross-head 25 of the actionslide M.

The forward portion of the trigger-plate unit I2 is formed with a vertical magazine-receiving passage 81 which is adapted to receive a boxmagazine 88 of a type common in repeating firearms.

The full automatic functioning of the firearm For purposes of making clear the operation of the gas-operated firearm herein chosen for purposes of illustration, let it be assumed that the control-unit 48 is at the limit of its movement from right to left and is turned into the position in which it is shown by full lines in Figs. 1, 4, 5, 15 and 16. When the control-unit 46 is in the position just referred to its control-stem 45 will be in a position of noninterference with the stopfinger 42 of the trigger 3", as is especially well shown in Fig. 5. It may further be assumed that the trigger 38 is held in its pulled position and that the firearm has just been discharged so that the parts assume the position in which they are shown in Figs. 1 and 3. 1 1

Under the conditions just above described,.gas under pressure created in the bore 36 of the barrel I I by the just-fired cartridge, will pass downwardly through the inclined gas-passage 35 into the forward-portion of the piston-chamber 32 in the cylinder-lug 33 and will impinge against the forward face of the head 3! of the piston 30.

The impingement just above referred to will drive the piston 36 rearwardly until the rear face of its head 3 I' engages with and is stopped by the forward face of the ring-like stop-member 34. During the relatively-short rearward travel of the piston to as just described, the stem 29 thereof will, through the intermediary of the rear-wall 28 of the crosshead 26, drive the action-slide I4 rearwardly to a much greater extent.

The initial rearward movement of the action slide I i under the urge of the piston 38, will cause the surfaces of the cam-recess 22 in the actionslide to coact with the actuating-lu 2| of the breech-bolt It to turn the said breech-bolt in a clockwise direction (as viewed from the front). This turning movement of the breech-bolt will disengage the locking-lugs I1 and I8 respectively from the locking-abutments I9 and 20 of the receiver It, to thus unlock the said breech-boltfor direct rearward travel. I

anchors Following the unlocking movement of the breech-bolt l3 as above described, the continued rearward movement of the action-slide 14 will move the said breech-bolt directly rearwardly to the limit of its rearward travel. The described rearward movement of the action-slide M will, of course, be accomplished against the tension of the breech-closing spring 83.

As the breech-bolt I3 is moved rearward-1y as above described, it will engage with and override the upper-portion of the hammer .63, to thereby swing the same in a counterclockwise direction (as viewed from the right) into an over-cocked position slightly beyond the position in which the said hammer is shown in Fig. 5. This described movement of the hammer 53 will bring the secondarymocking abutment 59 thereof to a position above the secondary-cocking abutment I! of the secondary-sear l I, In this connection, it is to be noted that as the action-slide l4 moves rearwardiy as above described, the tripping-abutment 1! thereof will ride clear of the trippingabutment 15 at the forward end of the sear-actuatin bar 45 to thus permit the said sear-actuating bar to be moved bodily rearwardly by the spring 8| to the limit of the movement permitted by the slot 18 and the coupling-pin 19, i. e., into the position in which the said sear-actuating bar 45 is shown in Fig. 5.

After the breech-bolt Ed has reached the limit of its rearward travel, the breech-closing spring 83 acting through the action-slide Ii, will assert itself to move the said breech-bolt forwardly. A short forward travel of the said breech-bolt from its rearmost position will cause the same to move out of engagement with the hammer 53 and thus permit the said hammer to turn slightly in a clockwise direction until the secondary-cocking abutment 68 thereof engages with the secondarycocking abutment ii! on the secondary-sear H, which latter is now at the limit of its rearward swing. Here again it is to be borne in mind that the trigger 38 is still held in its pulled position, as normally would be the case when the marksman is operating the firearm as a full automatic firearm.

After the breech-bolt l3 has moved forwardly sufiiciently to permit the hammer 63 to swing in a clockwise direction and thus engage the secondary-cocking abutments 69 and T0, the forward movement of the said breech-bolt will continue under the urge of the breech-closing spring 83 and the action-slide 14, until the respective rear faces of the locking-lugs I1 and 18 of the said breech-bolt are brought into registration with the locking-abutments l9 and 29 of the receiver 10. As soon as the registration just referred to takes place, the contours of the cam-recess 22 in the rear-portion 23 of the action-slide IE will turn the said breech-bolt in a counterclockwise direction, to thus lock the said breech-bolt against rearward movement so that the parts referred to will have assumed substantially the positions in which they are shown in Fig. 4.

After the parts have reached the position in which they are shown in Fig. 4, the action-slide M will continue its forward movement until it reaches the position in which it is shown in Fig. 1. During this latter movement, the tripping-abutment T! of the action-slide will engage with the tripping abutment 16 at the front of the sear-actnating bar 15, to thus move the said bar forward'ly. The described forward movement of the sear-actuating bar I?) will cause the said bar to act through the intermediary of its coupling-rim ger 1A and the coupling-notch 13 in the secondary-sear 11 to rock the said secondary-sear forwar-d'ly. The described rocking movement of the secondary-sear 1! will swing the secondary-cocking abutment 10 thereof out from under the secondary-cocking abutment 59 of the hammer 63. thus releasing the said hammer to again effect the discharge of the firearm and to repeat the cycle before described.

It is to be noted that the secondary-sear II is not turned sufliciently to release the hammer 63 until after the action-slide H has efi'ected the locking of the breech-bolt l3.

Should it be desired to lock the trigger 38 in a safe position, to thereby prevent the discharge of the firearm while the control-unit 46 is turned into position for full automatic fire as is shown in Figs. 1, 4, .5 and 15, the said control-unit 46 may be shifted from left to right along the axis of the control-stem 45, from the position in which it is shown in Fig. 15 into the position in which it is shown in Fig. 16. This shifting may be effected by manually pressing on the left end'of the control-stem .45.

described shifting of the control-unit 4 6 will, of course, be done while the trigger 3B is in its released position, in which position the stopfinger 42 of the said trigger is lifted. The shiftmg of the control-unit will cause the detent-rib 5i on the short face 49 of the web 48, to cam the detent-plunger 53 forwardly against the tension of the detentespring 55. Ultimately, in the travc1 of the control-stem 45 from left to right, the rear end of the detent-plunger 53 will ride down the left side of the detent-rib 5| and yieldingly hold the control-unit 46 in this safe position.

When the control-unit 46 is shifted as just above described, it will bring the full diameter of the left end of the cylindrical control-stem 45, beneath the stop-finger 42 of the trigger 38 and thereby prevent the said trigger from being pulled suificiently to release the hammer 63.

The semiautomatic functioning of the firearm When it is desired to so adjust the firearm that it will automatically reload but will require the release and subsequent pull of the trigger for each discharge, the control-lever 41 may be turned into the position in which it is indicated by broken lines in Fig. 4 and by full lines in Fig. 14, to thus turn the control-stem 45 into the position in which it is shown in Figs. 12, 13 and 14. The described turning movement of the controlunit 46 will of course, be effected while the same is in its non-safe position, i. e., it is shifted from right to left so that the trigger 38 may be pulled. Under these conditions the detentplunger 53 will lie to the right of the detent-rib 52 on the long face 50 of the web 48, as shown in Fig. 14.

It will be noted by reference to Figs. 12, 13 and 14 that when the control-unit 46 is turned as described, it is in a position whereby the short face 4.9 of its web 48 will be up and in a position to be engaged by the stop-finger 42 of the trigger 38 after the said trigger has been turned in a clockwise direction but a relatively-short distance, but before the said trigger can be fully turned into the position in which it is shown in Fig. 5.

For purposes of description let it be assumed that the parts are in substantially the positions in which they are shown in Fig. 12, in which it will be noted the trigger 38 is held in its pulled position and the hammer .63 is held in its cocked position by the secondary-sear "H. In the figure 9 last referred to, the breech-bolt I3 is in its breechclosing "position but the action-slide M will be in the position shown in Fig. 4, and has not as yet moved into its full forward position to cause the sear-actuating bar I5 to be moved forwardly sufficiently to turn the said secondary-sear into its hammer-releasing position.

The conditions illustrated in Fig. 12 may be assumed to have occurred immediately after the discharge of the firearm but before the marksman has had an opportunity to release the trigger 38 and before the action-slide has moved the searactuating bar [5 forwardly to release the hammer 63, though the breech-bolt I3 has been locked at breech-closing position as before referred to and much in the manner illustrated in Fig. 4.

The continued forward movement of the action-slide M from the position in which it is shown in Fig. 4 into the position in which it is shown in Figs. 1 and 3 (under the condition prevailing, however, in Fig. 12), will cause the tripping-abutment T! of the said action-slide to en gage with the re-arwardly-facing tripping-abutment 16 at the forward end of the sear-actuating bar I 5, so as to bodily move the said bar forwardly against the tension of the spring 8 I.

The described forward movement of the searactuating bar l5 will cause the same to act through the intermediary of its coupling-finger I4 and the coupling-notch 13 in the secondarysear H, to turn the said secondary-sear about its pivot-pin 12 and move the secondary-cocking abutment I8 forwardly out of engagement with the secondary-cocking abutment 69 on the hammer 63. This latter movement will release the hammer 63 to the action of the hammer-spring 65.

The described release of the hammer 63 will permit the said hammer to swing but a short distance under the conditions here prevailing, since the forward end of the primary-sear 56 will be in position to be engaged by the primary-cocking abutment 82 of the said hammer. The engagement just referred to will now occur and. will force the primary-sear 56 to move bodily a slight distance rearwardly against the tension of the sear-spring 60. This rearward bodily movement will only continue until the rear end of the said primary-sear engages with the forward face of the stop-rib 58 at the rear of the trigger 38, since the said trigger is, under the circumstances, still being held in its pulled position.

1 Now in the normal operation of the firearm, the marksman will in due course release the triggel 38 and permit the same to turn into the position in which it is shown in Fig. 13, whereupon the stop-rib 58 at the rear of the said trigger will be lowered. This lowering of the stop-rib 58 will permit the hammer 63 to force the primary-sear 56 further rearwardly against the tension of the sear-spring 50, until the forward wall of its transverse slot 51 engages with the forward-portion of the pivot-pin 4|, as is shown in Fig. 13. During the rearward travel of the primary-sear as just described, its rear-portion will move into a position overlying the upper surface of the stoprib 5B of the trigger 38.

The parts will now have assumed the positions in which they are shown in Fig. 13, in which figure, it will be noted, the secondary-sear H is swung forwardly out of action and the hammer 53 is held in its cocked position by the primarysear 56 in readiness for the discharge of the firearm when the trigger 38 is again pulled.

When the trigger 38 is again pulled it will act through its stop-rib 58 to turnthe primary-sear 56 in a clockwise direction and thus disengage the forward end of the said primary-sear from the primary-cocking abutment 62 of the hammer 63. The described action will cause the discharge of the firearm and the repetition of the cycle of semiautomatic operation above described.

Should it be desired to render the firearm safe while the control-unit 46 is turned into position to cause the firearm to operate as a semiautomatic weapon, the said control-unit may be manually shifted from left to right'in a manner similar to the shifting of the said unit fromthe position in which it is shown in Fig. 15 into the position in which it is shown in Fig. 16.

The shifting of the control-unit 46 from left to right as above described, will cause the detentrib 52 on the long face 50 of the web 48, to cam the detent-plunger 53 forwardly until suchtime as the said web has moved sufiiciently to the right to permit the said detent-plunger to ride down the left side of the said detent-rib 52 and into engagement with the portion of the long face 55 lying to the left of the detent-rib 52.

The full-diametered portion of the controlstem 45 of the control-unit 46 is more remote from the center of oscillation of the control-stem than is the short-face 49 thereof. The full diameter of the said control-stem may, therefore, be viewed as providing a safety-stop surface, inasmuch as it serves to check the movement of the trigger 38 beforethe' same can effect the discharge of the firearm regardless of whether the said control-stem is turned into either full-automatic setting or semiautomatic setting. The short-face 49 may be properly designated as providing a semiautomatic-stopsurface, inasmuch as it serves to limit the swinging movement of the trigger to just the amount required to cause the firearm to function as a semiautomatic firearm. The cutaway-portion of the control-stem 55 which is adjacent the back of the long-face '58, may be appropriately designated as a full-automatic clearance-portion, inasmuch as it serves (when in the position shown in Fig. 5) to permit the trigger 38 to be pulled far enough to effect the full-automatic operation of the firearm.

From the foregoing it will be seen that the detent-pluger 53 serves to 'yieldingly hold the control-unit in anyone of four different positions, i. e., automatic, semiautomatic, automatic-safe and. semiautomatic-safe positions.

It is to be noted that the control-unit may be turned around the central-longitudinal axisof its control-stem 45 while the said control-unit is at the extreme position to the right (Fig. 16). Thus, either full-automatic or semiautomatic may be pre-selected while the control-unit is in its safe position in readiness to be manually shifted from right to left when it is desired to operate the firearm.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essentia1 characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. A control-mechanism for automatic and semiautomatic firearms, including in combination: a trigger-and-sear unit including a trigger and a sear, the said trigger being opera- 11 tively connected to the said sear for moving the same, the said trigger-nnd-sear unit being also provided with a stop-portion engageabie with the hereinafter-mentioned control-member; a control-member mounted in the firearm-structure for axial reciprocation substantially crosswise of the path of movement of the stop-mention of the said trigger-and-wsear unit and for transverse oscillation, the said control-member being provided with a safety stop-surface located relatively remotely from its center of oscillation, the said control-member also being provided with a semiautomatic st0p-sur1ace located relatively closer to the center of osciliation -.of the control-member as compared to the location of the said safety stopsurface, the said semiautomatic stopsurface being out of circumferential alignment with the said safety stop'snrface, the said control-member aiso being formed with a full-automatic clearance-portion in circumferential alignment with the said -sewiim'l'mm-t-tic stop-surface, the said full-automatic clearance-portion being constructed and arranged to permit the said stopportion of the trigger-and-sear unit to move past the positions which are permitted by either the safety stop-surface or the semiautomatic stopsurface, the said control-member being movable axially relative to the stop-portion of the said trigger-and-sear unit to selectively bring either the safety stop-surface thereof or both the semiautomatic stop-smzface and the full-automatic clearance-portion into axial position for cooperation with the stop portion o! the said triggen and-sear unit, the said control-member being oscillata-ble about its axis at both extremes of its axial movement, whereby the "said controlmember may be moved from any given one of its three described positions directly into any one of the others thereof; and detent-means yieldingly holding the said control-member in any i 12 motely from its center of oscillation, the said control-member also being provided with a semiautomatic stop-surface located relatively closer to the center of oscillation of the control-member as compared to the location of the said safety stop-surface, the said semiautomatic stop-surface being out of circumferential alignment with the said safety stop-surface and having a length in an axial direction in excess of the amount of axial movement of the control-member, the said semiautomatic stop-surface being provided intermediate its opposite ends with a detent-projection, the said control-member also being formed with a full-automatic clearance-portion i-n circumferential alignment with the said semiautomatic stop-surface and having a bottom wall also of an extent in an axial direction exceeding the amount of axial movement of the control-member, the said full-automatic clearance-portion being constructed and arranged to permit the said stopportion of the trig-ger-and-sear unit to move past the positions which are permitted by either the safety stop-surface or the semiautomatic stopsurfaoe, the bottom wall of the said clearanceportion being provided intermediate its opposite ends with a detent-projection, the said controlmember being movable axially relative to the stop-portion of the said trigger-and-sear unit to selectively bring either the safety stop-surface thereof or both the semiautomatic stop-surface and the full-automatic clearance-portion into axial position for cooperation with the stop-portion of the said trigger-and-sear unit, the said control-member being oscillatable about its axis at both extremes of its axial movement whereby the said control-member may be moved from any given one of its three described positions directly into any one of the others thereof; and a yielding detent engageable with the respective detent-ribs of the semiautomatic stop-surface and the bottom Wall of the clearance-portion of the controlmember to yieldingly hold the control-member in any given one of its three said positions.

WILLIAM C. ROEMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 950,576 Paulson Mar. 1, 1910 2,324,125 Van Hornet a1 July 13, 1943 2,371,012 Woodhull Mar. 6, 1945 

